The (co)polymerization of olefins, especially olefins such as ethylene and propylene by themselves or with other olefins is one of largest parts of the worldwide chemical industry. The resulting polymers are useful in a myriad of ways, and therefore new methods of polymerizing these monomers and/or finding polyolefins with new and different structures are always of interest. Recently it was discovered that certain complexes of late transition metals could be used as part of polymerization catalyst systems for these olefins. Some of these catalyst systems produced polymers with unique structures.
Some of the complexes of late transition metals contained imino groups or various groups containing phosphorous, see for instance U.S. Pat. Nos. 6,177,528 and 5,986,027, World Patent Applications 00/20377, 01/92347, 99/50313,00/59956 and 98/40420, German Patent Application 199 47 519, and Japanese Patent Applications 99158213 and 00281710. None of the ligands and complexes described in these references is claimed herein, either as a composition or as part of a polymerization catalyst system.
The compound designated below as L2 and a complex with Pd is described in M. van der Sluis, et al., Organometallics, vol. 16, p. 1144–1152 (1997).
Polymerization of ethylene using phosphinidine-palladium catalysts has been described by F. Ozawa, M. Yoshifuji et. al., Angew. Chem. Int. Ed. Engl., vol. 39, p. 4512 (2000). None of the phosphinidines mentioned in this article are the subject of the present claims.